We plan to determine the function of rat liver alkaline phosphatase by 1) attempting to identify a specific inducer of alkaline phosphatase and 2) by observing changes in bile flow and bile composition produced by specific inhibition of rat liver alkaline phosphatase using either monospecific antibody to alkaline phosphatase or site-specific reagents that will covalently bind at alkaline phosphatase's active center. We will use organ culture, incubation of isolated hepatocytes and isolated perfused rat livers in the above experiments. We propose to study the catabolism of alkaline phosphatase, identify the site or sites at which catabolism occurs and isolate free systems capable of hydrolyzing alkaline phosphatase. We hope to develop affinity columns that will facilitate the purification of alkaline phosphatase. We plan to purify to homogeneity human liver, bone, kidney and intestinal alkaline phosphatase and study their protein structure. We propose to prepare specific antibodies to each of these enzymes and to develop radioimmunoassays to facilitate the measurement of each isoenzyme in human serum. Finally, we plan to study the mechanisms of the elevated serum alkaline phosphatase in humans with liver disease to determine if it is the same as that which we demonstrated in rats.